By its very nature, the Internet provides a certain degree of anonymity to Internet users. Notably, Internet users are not required to identify themselves before logging on to the Internet. Internet transactions are also not centrally recorded, making it difficult to piece together a user's online transactions across different websites and systems.
One prominent technology used to address the lack of a central recordation function in the Internet is a browser cookie. Generally, a browser cookie is a piece of data that a website can set on a user's browser, to store information about the user's transaction with the website. For example, a browser cookie may include login information, transaction state information, or other information that the browser passes back to the website during a given session. Using the returned cookie, the website is able to record transaction information as the user traverses different pages of the website.
Since cookies are tied to the domain/website of the issuer, their use as a recordation mechanism is limited across different websites. For example, assume that website A sets a browser cookie A′ on the browser. In turn, website A is able to use browser cookie A′ to record transaction information when the browser visits the various webpages of website A. However, if the user then navigates to website B, cookie A′ will be unable to provide transaction information to website A regarding the visit to website B. Accordingly, the notion of a pixel tag was developed. Generally, a pixel tag is a link to an otherwise invisible image (e.g., a 1×1 pixel image) that is embedded into a webpage of interest. Continuing the above example, assume now that a webpage of website B includes a pixel tag linked to website A. Thus, when the browser loads the webpage of website B, the browser will also send an image request to website A, allowing website A to use cookie A′ to record the browser's visit to the webpage of website B.
Challenges persist, however, to capture online transaction information in many other scenarios. For example, consider the case in which a browser follows a link from website C to D. If the transaction recording system is unaffiliated with one or both websites, it will not be able to capture information regarding this transaction.